1. Field of the Invention
This invention concerns metallic pipe locators in general. More specifically, it concerns a particularly effective metallic pipe locator that is applicable to finding buried pipes such as pipelines or the like.
2. Description of the Prior Art
There have been numerous prior proposals for different types of instruments that are applicable to determining the location of buried metallic pipe. One type uses a magnetometer to sense anomalies in the earth's magnetic field which are caused by buried metallic objects. However, there are practical difficulties, and in any event such type of instrument is not relevant to the type of locator according to this invention.
Known prior locators of the type to which this invention is applicable, have required as part of the locator, the application of a transmitter signal to the metallic pipe. This meant that the pipeline to be located had to be accessible at a nearby point for attaching the transmitter, or the transmitter had to be brought into close proximity to the line in order to couple an electromagnetic signal to the line. The latter often required two operators one for the transmitter and one for the receiver.
Furthermore, known prior systems have usually involved radio frequency transmitter signals, which added to the complexity of the receiving instrument at least.
Consequently, it is an object of this invention to provide a very simple and yet highly effective instrument for locating buried pipes or pipelines.